JEE Main 2022 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 30 June 2022, Shift 1, Physics Q48

Question 48 of 90 in this shift, Physics question 18 of 30, Section A.

A source of monochromatic light liberates

9\times10^{20}

photon per second with wavelength 600 nm when operated at 400 W. The number of photons emitted per second with wavelength of 800 nm by the source of monochromatic light operating at same power will be :

(1) $12\times10^{20}$ Official answer
(2) $6\times10^{20}$
(3) $9\times10^{20}$
(4) $24\times10^{20}$

Official answer

Option 1

NTA final key.

Chapter: Dual Nature of Radiation and Matter
Topic: Photoelectric Effect
Idea tested: Photon Flux and Beam Power

Same idea in other shifts

Asked 7× in all

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.